Auxiliary refrigeration power means

ABSTRACT

In an engine powered with a generator and a storage battery a vehicle having a refrigerated compartment with a refrigeration system having a cooling coil, a compressor connected to the cooling coil, a condensor connected to the compressor, an expansion valve or the like connected to the compressor and to the cooling coil an improvement in an embodiment having a second compressor connected in parallel with the first compressor and being operated by a direct current electric motor powered by the storage battery and in another embodiment having a direct current electric motor powered alternately by the storage battery or by a rectifier. The improvement has a control to operate the system relative to the refrigeration demand of the system.

United States Patent 1191 Krug 1451 Feb. 18,1975

1 1 AUXILIARY REFRIGERATION POWER MEANS [75] Inventor: Lawrence M. Krug, Wichita, Kans.

[73] Assignee: George C. Jeffreys, Goldsboro, NC.

[22] Filed: Sept. 12, 1973 [21] Appl. No.: 396,387

[52] U.S. Cl 62/229, 62/236, 62/510, 62/215, 62/226, 62/239, 62/298, 62/178 [51] Int. Cl. F25l [58] Field of Search 62/229, 236, 510, 298, 62/239, 178

[56] References Cited UNITED STATES PATENTS 1,985,639 12/1934 King 62/236 2,089,512 8/1937 Upp l 62/236 2,231,069 2/1941 Harris 1 62/229 2,319,130 5/1943 Hanson 62/236 2,608,066 8/1952 Kirkpatrick 62/229 2,740,904 4/1956 Goss 62/236 2,743,589 5/1956 Kucmpel 62/243 3? /0 EVAPOP/l 7'0? 0/? COOL/MG C'Q/L Fricke 62/236 Farer 62/236 [57] ABSTRACT In an engine powered with a generator and a storage battery a vehicle having a refrigerated compartment with a refrigeration system having a cooling coil, a compressor connected to the cooling coil, 21 condensor connected to the compressor, an expansion valve or the like connected to the compressor and to the c ooling coil an improvement in an embodiment having a second compressor connected in parallel with the first compressor and being operated by a direct current electric motor powered by the storage battery and in another embodiment having a direct current electric motor powered alternately by the storage battery or by a rectifier. The improvement has a control to operate the system relative to the refrigeration demand of the system.

9 Claims, 7 Drawing Figures D. C. COMP/Q6550? AUXILIARY REFRIGERATION POWER MEANS BACKGROUND OF THE INVENTION The invention is related to refrigeration systems powerable from either of two alternately available sources of electrical power. Numerous types of refrigeration systems are known in the prior art which are alternately powerable from two sources of power, namely, an electric motor being one source and a hydraulic motor or an internal combustion engine being the other source of power. In these known systems a single compressor of the shaft driven piston type is connected by belts, pulleys and clutches to the electric motor and to the hydraulic motor or internal combustion engine so either power source can rotate the compressor shaft. Refrigeration apparatuses are known in the art which are operable from the power takeoff of a vehicle such as a truck or bus. in these cases the power takeoff operates a hydraulic system having a hydraulic motor which is connected to the compressor as described. Some of these power take-off operated systems have a second compressor driven directly from the vehicles power takeoff and connected in the refrigerant circuit to accomplish the alternate powering. In the refrigeration art direct current electric motors are not generally used to operate refrigeration compressors for the reason that dependable direct current electric motors that can be economically operated on low voltages have not been available. In the prior art many vehicles have refrigerated compartments, for example, ice cream vending trucks, milk trucks, frozen food or refrigerated food delivery trucks, some campers, travel trailers and motor homes. In these vehicles some use dry ice for cooling and some have refrigeration systems which are powered by liquid petroleum gas or by a mechanical apparatus. Of those having a mechanical apparatus some have a refrigeration system wherein the compressor is powered by a small auxiliary internal combustion engine operated solely for the purpose of maintaining the refrigerated compartment. In some of the vehicles a series of cooling plates are provided which are frozen or substantially cooled by a refrigeration system having an electric motor which is powered by an alternating current power source during times when the truck is not in use, such as at night when the truck is not in service. No devices are known in the prior art which will operate a refrigeration apparatus in a vehicle from the direct current power source of the vehicle or from an al ternating current power source to maintain the refrigerated compartment of the vehicle.

SUMMARY OF THE INVENTION The apparatus ofthis invention is presented herein in several embodiments thereof. The several embodiments all function generally similar in that they can be powered from an alternating current electrical power source or a direct current electrical power source, and they are specifically adapted for use with an engine powered vehicle having a storage battery. In an embodiment, l of the refrigeration power means of this invention such has a refrigerant circuit including a refrigerant storage container, a compressor powerable from an alternating current electrical power source and another compressor powered by a direct current electric motor from a source of direct current electrical power connected in parallel with the first-named com pressor and being operable alternately with the firstnamed compressor. In another embodiment, (2), ofthe refrigeration power means of this invention, such has a refrigerant circuit without a refrigerant storage container, and having a compressor powerable from a source of alternating current electrical power and having another compressor powered by a direct current electric motor from a source of direct current electric power connected in parallel with the first-named compressor and being operable alternately therewith. In another embodiment. (3), of the refrigeration power means of this invention, such has a refrigerant circuit including a pair of compressors, a pair of condensors.

and a pair of refrigerant storage containers therein with the compressors, condensors, and refrigerant storage containers being connected in a parallel relation, one of the compressors having an alternating current electric motor powerable from a source of alternating current electrical power and the other compressor having a direct current electric motor powerable from a source of direct current electric power. In another embodiment, (4), of the refrigeration power means of this invention. such has a refrigerant circuit with a single compressor therein, the compressor connected to a direct current electric motor and the direct electric motor receiving power from a power supply which is connected with a battery and connectable with a source of alternating current electrical power and operable to supply the motor with electrical power either from the battery or from the alternating current power source via a rectifier. In this embodiment the power supply is removably connectable with the direct current electric motor and the control for the motor. In another embodiment, (5), of the refrigeration power means of this invention, such has a refigerant circuit with a compressor therein, the compressor connected to a direct current electric motor for rotation thereof the further having a power supply connected with a battery and connectable with a source of alternating current electrical power to alternately supply the motor with direct current electrical power from the battery or from the alternating current power source via a rectifier.

One object of this invention is to provide a refrigeration power means overcoming the aforementioned disadvantages of the prior art devices.

Still, one object of this invention is to provide a refrigeration system for the refrigerated compartment of a vehicle wherein the refrigeration system can be powered from the vehicles conventional storage battery power source and powered alternately from a source of alternating current electrical power.

Another object of this invention is to provide a refrigeration system having two compressors in the refrigerant circuit, one of the compressors being powerable from a source of alternating current electric power by an electric motor and the other compressor being powerable from a source of direct current electric power by an electric motor wherein either of the compressors may be alternately operated to maintain the refrigerated compartment in the desired refrigerated condition.

Yet, another object of this invention is to provide a refrigeration power means for a vapor compression refrigeration circuit having a compressor therein which is powered by a direct current electric motor that is alternately supplied with electrical power from a storage battery or from a source of alternating current electrical power through a power supply having a rectifier and further with the power supply being constructed so that in the event of an alternating current power failure it will automatically switch to operate the motor from the battery.

Yet, another object of this invention is to provide a refrigeration power means as described immediately above wherein the power supply is removably connectable with the electrical circuit of a refrigeration system and'additionally has the capability of operating a freezing compartment lid molding heater or the like from the alternating current electrical power source.

Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the accompanying drawings, in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a vapor compression refrigeration system having an embodiment, (1), of the refrigeration power means which has two compressors and a single refrigerant storage container;

FIG. 2 is a schematic diagram of a vapor compression refrigeration system having an embodiment, (2), of the refrigeration power means which has two compressors;

FIG. 3 is a schematic diagram ofa vapor compression refrigeration system having an embodiment, (3), of the refrigeration power means which has two compressors, two condensors, and two refrigerant storage containers;

FIG. 4 is a schematic diagram ofa vapor compression refrigeration system having an embodiment, (4), of the refrigeration power means which includes a direct current electric motor and power supply therefor, with the power supply being removably connectable as indicated by the dashed line;

FIG. 5 is a schematic diagram ofa vapor compression refrigeration system having an embodiment, (5 of the refrigeration power means, such having a direct current electric motor and a power supply therefor;

FIG. 6 is a perspective view of a top opening chest type freezer having portions thereof cut away for clarity, showing the compressor, motor, and condensor unit therefor removed and showing the power supply adjacent thereto; and

FIG. 7 is a perspective view, taken from above, of a typical ice cream vending truck or the like having the freezing compartments, refrigerator apparatus and power supply shown in FIG. 6 mounted therein, the truck being shown in outline.

The following is a discussion and description of preferred specific embodiments of the auxiliary refrigeration power means of this invention, such being made with reference to the drawings, whereupon the same reference numerals are used to indicate the same or similar parts and/or structures. It is to be understood that such discussion and description is not to unduly limit the scope of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings generally, an embodiment, (I), of the invention is shown in FIG. 1 and generally indicated at 10; another embodiment, (2), of the invention is shown in FIG. 2 and generally indicated at 12; another embodiment, (3), of the invention is shown in FIG. 3 and generally indicated at 14; another embodiment, (4), of the invention is shown in FIG. 4 and generally indicated at 16; and another embodiment, (5 of the invention is shown in FIG. 5 and generally indicated at 18.

5 Referring to FIG. 1 in detail, such shows an embodiment, (1), of the auxiliary refrigeration power means of this invention having the power means 10 integrally connected in a vapor compression refrigeration circuit. The refrigeration circuit and the elements of the power means 10 are shown as schematic symbols or in representative diagram-like form to illustrate the connection and coaction therebetween. The vapor compression refrigeration circuit includes a condensor 20 connected by a conduit 22 to a refrigeration storage container or receiver tank 24 which is connected by a conduit 26 to an expansion valve or the like 28 which is connected by a conduit 30 to the evaporator or cooling coil 32 which is connected by a conduit 34 to the inlets of a motorcompressor unit 36 and a compressor 38 which are connected in parallel, each having outlet conduits 40 and 42, respectively, and check valves 44 and 46, re-

spectively, with the check valves 44 and 46 connected to a single conduit 48 joining their outlets with the inlet of the condensor 20.

The condensor 20 is preferably a conventional free flow type having an inlet and an outlet and being compatible capacity wise with the compressors, the evaporator or cooling coil 32 and the refrigerated compartment. The refrigerant storage container or receiver tank 24 is provided as a refrigerant accumulator for accumulation of substantially saturated refrigerant, such being an element commonly used in the art. The expansion valve or the like 28 may be an expansion valve or a capillary tube, either of which function similarly in a throttling process to expand the compressed refrigerant in a condition of substantially constant enthalpy. The evaporator or cooling coil 32 is preferably constructed in the wall of the refrigerated compartment and may be varied in specific structure depending upon the intended operating temperature of the refrigerated compartment and the physical structure thereof.

The motor-compressor unit 36 is preferably a motor and compressor unit, such being labeled as an AC. COMPRESSOR for identification purposes. The motor-compressor unit 36 has the motor and compressor enclosed in a single housing with an inlet and an outlet for the refrigerant, connections for electrically connecting the motor portion thereof with an alternating current electrical power source 50 and connections for electrically joining the motor with a thermostatic switch 52 for controlling on and off operation of the motor. The compressor 38 is preferably a conventional piston type compressor having a rotatable shaft. A direct current electric motor 54 is provided to operate the compressor 38 and has the rotatable shaft thereof connected with the rotatable shaft of the compressor 38, preferably by a belt and pulleys. The direct current electric motor 54 is preferably of the permanent magnet type. The compressor 38 is driven only from the direct current electric motor 54 and is labeled as a DC. COMPRESSOR for identification purposes. The compressor 38 has the inlet thereto connected to the conduit 34 from the outlet of the evaporator or cooling coil 32, and it has the outlet therefrom connected to the conduit 42 which is connected with the check valve 46. The check valves 44 and 46 allow refrigerant to pass from the respective compressors as indicated by the arrows and are provided to prevent one compressor from forcing compressed refrigerant, oils, and other materials which may be in the refrigerant circuit into the discharge of the other compressor. The outlets of the check valves are connected by conduits to a juncture point and by a single conduit 48 therefrom to the inlet of the condensor 20. Preferably, the compressors have substantially the same hose power rating so they will function substantially equally in the refrigeration sys tem to evacuate the evaporator 32 and to compress the refrigerant.

Control for the direct current electric motor 54 and in turn the compressor 38 is accomplished by a pressure activated control switch 56 connected by a conduit 58 with the conduit 34 and electrically connected with the motor 54. As the temperature in the refrigerated compartment varies, the pressure in the conduit of the evaporator or cooling coil and its outlet conduit 34 will vary accordingly as is well known in the art, thus providing the activating force for actuating the pressure sensitive control switch 56 to turn on and off the electric motor 54. The pressure sensitive control switch 56 has bellows or the like operably connected to a pair of switches 60 and 62. The pressure sensitive control switch 56 is preferably adjustable to open and close the switches 60 and 62 at predetermined certain pressure valves relative to atmospheric pressure. The control circuit further includes a storage battery 64, a master control switch 66 and a cooling fan having a direct current motor 68. The cooling fan is preferably provided in position to force air over the motor 54 and compressor 38 while they are in operation. Practice of this invention has shown the cooling fan to be helpful in reducing operating temperatures of the motor 54 and compressor 38 thereby providing for increased operating efficiency and prolonging their useful life. The bat tery 64 is connected to the compressor motor 54, the fan motor 68, the master control switch 66, and the pressure sensitive control switch 56. A generator or the like 65 is provided for charging the battery 64; such is the generator of the vehicle on which the power means is used. Closing of the master control switch 66 completes the circuit connecting the battery 64 with the pressure sensitive control switch 56 and the motor 54 and 68. One control switch 60 in the pressure sensitive control switch 56 is connected to control operation of the direct current electric motor 54 that is connected with the compressor 38. The other control switch 62 in the pressure sensitive control switch 56 is connected to control operation of the fan motor 68. An increase in temperature in the refrigerated compartment corresponds to an increase in pressure, relative to atmospheric pressure, in the evaporator or cooling coil 32 and also an increase in pressure in the conduit 34. When the pressure reaches a predetemined certain value, it causes the pressure sensitive control switch 56 to close the switches 60 and 62, thus connecting the battery 64 with the compressor motor 54 and the fan motor 68 so that they will operate. As the compressor 38 operates, temperature and pressure in the evaporator 32 are reduced. When a predetermined and certain temperature is reached in the refrigerated compartment, a predetermined and certain pressure is also reached in the conduit 34 which causes the pressure sensitive control switch 56 to open the switches 60 and 62 thereby terminating operation of the direct current electric motor 54, the compressor, 38, and the fan motor 68. It is to be noted that specific ratings, capacities and sizes of the elements of the refrigeration system can be picked to provide for a refrigerated compartment which is only slightly cooled, such as in the temperature range of household refrigerators, water coolers, etc., or such can be picked to provide for subzero F. temperatures necessary for storage of frozen foods.

In practice the refrigeration power means 10 has been constructed and used with a vapor compression refrigeration system for a freezing compartment in an ice cream vending truck of the type normally making street sales in residential areas. The freezing compartment operated by the auxiliary refrigeration power means 10 has maintained a temperature between l2 F. and 3 F. which is a temperature suitable to maintain ice cream and similar confections in a solid frozen state when the vending truck is in daily use on a route making frequent stops. The auxiliary refrigeration power means has been used consistently to maintain a temperature in the freezing compartment as described during periods of the summer when outside air temper ature is above F. and the temperature inside the vending truck is 120 F. or higher. In such practice the compressors are rated at approximately /a horse power and the direct current electric motor 54 is rated at approximately /3 horse power. The pressure sensitive control switch 56 is preferably set to operate the compressor motor 54 and compressor 38 to maintain the temperature conditions of the refrigerant in the evapo rator or cooling coil 32 as described above. In practice a halogenated hydrocarbon refrigerant, dichlorodifluoromethane, was used; this refrigerant is commonly known in the art by its trade name FREON-IZ. In such practice the refrigerated compartment was a commercially available top opening chest type freezer. A model BF freezer produced by the Universal Noland Cabinet Company of Conway, Arkansas, has been used. A freezer of this general type is shown in FIG. 6. Also, a model DF-l4 Kelvinator freezer has been used. The Kelvinator freezer differs from the other type of freezer in that it uses a radiant shell type condensor instead of a free flow type condensor. Additionally, in such practice the motorcompressor unit 36 was operated from normal line power, volts A.C. and the direct current electric motor 54 was operated from the 12 volt storage battery of the vending truck.

In the use and operation of the auxiliary refrigeration power means 10 of this embodiment, l of this invention, such provides for powering the refrigeration apparatus from an alternating current power source or alternately from a storage battery. During periods when an alternating current power source is available, such as when an ice cream vending truck or the like is in a garage or the like where it is stored when not in use or being loaded with ice cream and other confections or the like, the electrical power source 50 is connected with the motor-compressor unit 36 by a plug or the like (not shown in the drawings) so it will operate and the master switch 66 is put in the open position. When the alternating current power source 50 is connected, the master control switch 66 must be in the open position as shown in FIG. 1 so the motor 54 and compressor 38 will not operate. When the motor-compressor unit 36 is connected for operation, the A.C. compressor functions in the refrigeration circuit to compress the refrigerant and pass same to the condensor 20. The temperature sensitive thermostatic control switch 52 controls operation of the motor-compressor unit 36 to maintain the refrigerated compartment in the desired refrigerated condition. When the ice cream vending truck or the like leaves the garage or the like the source of alternating current electrical power is no longer available. At this time the alternating current power source is disconnected from the motor-compressor unit 36 and the master control switch 66 is put in the closed position so the motor 54 and compressor 38 can function as needed to maintain the refrigerated compartment in the desired refrigerated condition until the truck returns and the alternating current power source can again be used. The pressure sensitive control switch 56 will turn the motor 54 on and off as described to oper' ate the compressor and maintain the refrigerated condition. The battery 64 is preferably the storage battery of the vehicle having the auxiliary refrigeration power apparatus. In practice the auxiliary refrigeration power means of this embodiment, 1 of this invention has been used operating same from the storage battery of an ice cream vending truck. In this practice it has been found that the conventional electrical system of the vehicle. including the generator. has been sufficient to adequately operate the vehicle including music reproduction equipment normally used in conjunction with sales of such confection products and operate the direct current electric motor 54 when the outside air temperature is above 100F. on a daily basis. An additional feature of the auxiliary refrigeration power means 10 of this invention which is to be noted is that in the case of a power failure or other failure which would affect the alternating current supply or the motor-compressor unit 36 during times when the vehicle is in the garage or the like, then the refrigerated comparment of the vehiclecan be maintained by the auxiliary refrigeration power means from the storage battery of the vehicle. Obviously, sustained operation of the motor 54 will eventually run down the storage battery 64 if it is not recharged. However, such would provide an extended time to make repairs to the apparatus or make arrangements to prevent spoilage or loss of products stored in the refrigerated compartment.

Referring to FIG. 2 in detail, such shows an embodiment, (2), ofthe auxiliary refrigeration power means of this invention having the power means 12 integrally connected in a vapor compression refrigeration circuit. The refrigeration circuit and the elements of the auxiliary refrigeration power apparatus 12 are shown as schematic symbols or in a representative diagram-like form to illustrate their connection and coaction. The vapor compression refrigeration circuit includes a condensor 80 connected by a conduit 82 to an expansion valve or the like 84 which is connected by a conduit 86 to the evaporator or cooling coil 88 which is connected by a conduit 90 to the inlets ofa motor-compressor unit 92 and a compressor 94 which are connected in parallel, each having outlet conduits 96 and 98, respectively, and check valves 100 and 102, respectively, connected with the conduits 96 and 98 with the check valves 100 and 102 communicably connected to a single conduit 104 joining the outlets of the check valves with the inlet of the condensor 80.

The condensor 80 is preferably a conventional free flow type condensor to transfer heat to the atmosphere, having an inlet and an outlet and being capacitywise compatible with the compressors, and the evaporator or cooling coil 88 in the refrigerated compartment. The

expansion valve or the like 84 may be an expansion valve or a capillary tube since either are elements which function similarly in a throttling process to expand the compressed refrigerant in a condition of substantially constant enthalpy. The evaporator or cooling coil 88 is preferably constructed in the walls of the refrigerated compartment and may be varied in specific structure depending upon the intended operating use and operating temperatures of the refrigerated compartment and the physical requirements therefor.

The motor-compressor unit 92 is preferably a motor and compressor combined in a single structural unit. such being labeled as an A.C. COMPRESSOR for identification purposes. The motor-compressor unit 92 has the motor and compressor thereof enclosed in a single unitlike housing with an inlet and an outlet for the refrigerant, electrical connections for the motor portion thereof with an alternating current power source which is indicated at 106 and additionally having electrical connections for connecting a thermostatic switch 108 with the motor for controlling its on and off operation. It is to be noted that the thermostatic switch 108 can be connected with a relay or the like and placed between the alternating current power source 106 and the motor portion of the motor-compressor unit 92. The compressor 94 is preferably a conventional piston type compressor having a rotatable shaft. A direct current electric motor 110 is provided to operate the compressor 94, and it has the rotatable shaft thereof connected with the rotatable shaft of compressor 94, preferably by a belt and pulleys. The motor 110 is preferably of the permanent magnet type. The compressor 94 is driven only from the direct current electric motor 110 and is labeled D.C. COMPRESSOR for identification purposes. The compressor 94 has the inlet thereto connected to the conduit from the outlet of the evaporator or cooling coil 88, and it has the outlet therefrom connected to the conduit 98 joining same with the check valve 102. The check valves and 102 allow the refrigerant to pass from the respective compressors as indicated by the arrows but do not allow a reverse flow. The check valves are provided to prevent one compressor from forcing compressed refrigerant, oils, and other materials which may be in the refrigerant circuit into the discharge or outlet of the other compressor. The outlets of the check valves 100 and 102 are connected by conduits to a juncture point where a single conduit 104 from the juncture point connects to the inlet of the condensor 80. Preferably, the compressors have substantially the same horse power rating so they will function substantially equally in the refrigeration system to evacuate the evaporator or cooling coil 88 and to compress the refrigerant.

Control for the direct current electric motor is partiallyaccomplished by a pressure sensitive control switch 112 connected by a conduit 114 with the outlet conduit 90 from he evaporator or cooling coil 88. The pressure sensitive control switch 112 includes bellows or the like operably connected to a pair of switches 116 and 118. The pressure sensitive control switch 112 is preferably adjustable to open and close the switches 116 and 118 at predetermined certain pressure values, preferably relative to atmospheric pressure. As the temperature in the refrigerated compartment varies, the pressure of the refrigerant in the conduit of the evaporator or cooling coil 88 and its outlet conduit 90 will vary accordingly as is well known in the art. This variation in pressure provides the activating force for operating the pressure sensitive control switch 112 to open and close the switches 116 and 118. The control circuit for the electric motor 110 includes a storage battery 120, a master control switch 122 and a cooling fan having a direct current electric motor 124. A generator or the like 121 is provided for charging the battery 120; such is the generator of the vehicle on which the power means 12 is used. Thecooling fan is preferably provided in position to force air over the motor 110 and compressor 94 while they are in operation. Practice of this invention has shown the cooling fan to be helpful in reducing the operating temperature of the motor 110 and the compressor 94 thereby providing for increased operating efficiency and prolonging their useful life. The storage battery 120 is connected to the motor 110, the fan motor 124, the master control switch 122 and the pressure sensitive control switch 112. Closing the master control switch 122 completes the circuit connecting the battery 120 with the pressure sensitive control switch 112 and the motors 110 and 124. One control switch 116 in the pressure sensitive control switch 112 is connected to control operation of the compressor motor 110 and the other switch 118 is connected to control operation of the cooling fan motor 124. An increase in temperature in the refrigerated compartment corresponds to an increase in pressure, relative to atmospheric pressure, in the evaporator or cooling coil 88 and also an increase in pressure in the conduit 90. When this pressure reaches a predetermined certain value, it causes the pressure sensitive control switch 112 to close the switches 116 and 118, thus connecting the storage battery 120 with the compressor motor 110 and the fan motor 124 so they will operate. As the compressor operates, the temperature and pressure in the evaporator 88 are reduced. When a predetermined and certain temperature is reached in the refrigerated compartment, then predetermined and certain pressure is also reached in the conduit of the evaporator 88 and the conduit 90 which causes the pressure sensitive control switch 112 to open the switches 116 and 118 thereby terminating operation of the compressor motor 110 and the cooling fan motor 68. it is to be noted that specific ratings, capacities, and sizes of the elements of the refrigeration system can be picked to provide for a refrigerated compartment which is only slightly cooled, such as in the temperature range of household refrigerators, water coolers, etc., or such can be picked to provide for subzero F. temperatures necessary for storage of frozen foods.

In practice, the refrigeration power means 12 has been constructed and used with a vapor compression refrigeration system for a freezing compartment in an ice cream vending truck of the type normally used in making street sales in residential areas. The freezing compartment is maintained by the auxiliary refrigeration power means 12 at a temperature between 1 2 F. and 3 F. which is a temperature suitable to maintain ice cream and other confections sold by such venders in a solid frozen state when the vending truck is in daily use on a route and making frequent stops. The auxiliary refrigeration power means has been used consistently to maintain the temperature in the freezing compartment as described during periods of the summer when the outside air temperature is above 100 F. and the temperature inside the vending truck and adjacent to the exterior of the freezing compartment is 120 F. or

higher. In such practice, the compressors are rated at approximately Va horse power and the direct current electric motor connected with the compressor 94 is also rated at approximately /3 horse power. The pres sure sensitive control switch 112 is preferably adjusted to operate the motor 110 and compressor 94 such that the refrigerant in the evaporator 88 will be maintained in the described range. In practice a halogenated hydrocarbon refrigerant, dichlorodifluoromethane, was used. Additionally, in such practice the refrigerated compartment used was a commercially available topopening chest type freezer. A model DF 14 freezer produced by the Kelvinator Company has been used. This particular model of freezer has a radiant shell condensor which radiates the heat to the atmosphere through the exterior shell of the freezer structure. In the construction of such a condensor in the vapor compression refrigeration circuit, refrigerant storage containers may not be necessary as the volume of the refrigerant can be accumulated in the radiant shell condensor. It is to be noted that freezers other than the type and model described can be used with the auxiliary refrigeration power means of this invention. In such practice the motor-compressor unit 92 was operated from normal line power, volts AC, and the direct current electric motor 110 was operated from the 12 volt storage battery of the vending truck.

Use and operation of the auxiliary refrigeration power means 12 of this embodiment, (2), of this invention enables a freezing compartment in a vehicle to be operated from an alternating current power source or in the alternative from the vehicle's storage battery. The auxiliary refrigeration power means 12 is adapted for use with a vapor compression refrigeration circuit which does not have a refrigerant storage container therein and which has a radiant shell type condensor. During times when an alternating current power source is available, such as when an ice cream vending truck or the like is in the garage or in storage when it is not being used or when it is being loaded with products for sale, the alternating current electrical power source 106 is connected to the motor-compressor unit 92 by a plug or the like (not shown in the drawings) so it will operate same and maintain the freezing compartment in the described temperature range for storage of the products. When the alternating current power source 106 is connected with the motor-compressor unit 92, the master switch 122 is put in the open position so the direct current electric motor 110 will not operate. When the vending truck leaves the garage or the like and the alternating current electrical power source 106 is no longer available, the master switch 122 is put in the closed position so the motor 110 will operate as needed. When the vending truck is on the route, the auxiliary refrigeration power means 12 will operate as described to maintain the conditions of the freezing compartment until the truck returns and the alternating current power source 106 can be reconnected. An additional feature of the auxiliary refrigeration power means 12 is that during periods when the vending truck or the like is in the garage and would normally be connected with the alternating current power source 106 for operation and in the event of a power failure or other failure which would prevent the motorcompressor unit 92 from operating, the refrigerated compartment can be maintained by the auxiliary refrigeration power means 12 by simply putting the master switch 122 in the on" condition. During times when there is a filure in the alternating current power source 106 or in any other failure which prevents the motorcompressor unit from operating, the auxiliary refrigeration power means 12 can be used to maintain the conditions in the refrigerated compartment for a substantial time. Obviously, sustained operation of the motor 110 will eventually run down the storage battery of the vehicle; however, such would provide a longer period of time to make repairs to the apparatus or to make arrangements to prevent spoilage or loss of products stored in the refrigerated compartment.

Referring to FIG. 3, such shows an embodiment, (3), of the auxiliary refrigeration power means of this invention having the power means 14 integrally connected in a vapor compression refrigeration circuit. The refrigeration circuit and the elements of the power means 14 are shown as schematic symbols or in representative diagram-like form to illustrate their connection and coation. The vapor compression refrigeration circuit includes a condensor 130, labeled A.C. CONDENSOR connected by a conduit 132 to a refrigerant storage container or receiver tank 134 which is connected by a conduit 136 to a check valve 138 which is connected by a conduit 140 to an expansion valve or the like 142 which is connected by a conduit 144 to an evaporator or cooling coil 146 which is connected by a conduit 148 to the inlet of a motor-compressor unit 150 and to another compressor 152. The motor-compressor unit 150 is connected by a conduit 154 to the A.C. CON- DENSOR 130. The condensor 130 can be a radiant shell type condensor or a conventional free flow type heat exchanger structure. The refrigerant storage container 134 or receiver tank is provided for accumulation or temporary storage of substantially saturated refrigerant, such being an element commonly used in the art. The expansion valve or the like 142 may be an expansion valve or a capillary tube, either of which function similarly in a throttling process to expand the compressed refrigerant in a condition of substantially constant enthalpy. The evaporator or cooling coil 32 is preferably constructed in the wall of the refrigerated compartment and may be varied in specific structure depending upon the intended operating temperature of the refrigerated compartment and the physical structure thereof.

The motor-compressor unit 150 is preferably a motor and compressor unit enclosed in a single housing with an inlet and an outlet for the refrigerant, electrical connections for connecting the motor thereof with an a]- ternating current electrical power source 156. It can have electrical connections for a thermostatic switch 158 used for controlling on and off operation of the motor.

The auxiliary refrigeration power means 14 includes the compressor 152, a condensor 160, labeled D.C. CONDENSOR, connected by a conduit 162 with the outlet of the compressor 152, a conduit 164 connecting the outlet of the condensor 160 with the inlet of a receiver tank or refrigerant storage container 166 connected by a conduit 168 to a second check valve 170 which is connected to the conduit 140. The check valve 170 allows the refrigerant to pass from the refrigerant storage container 166. A direct current electric motor 172, labeled D.C. MOTOR is connected with the compressor 152 for the operation thereof. The compressor 152 is preferably a piston type compressor having a ro- 12 tatable shaft connected with the shaft of the electric motor 172 preferably by a belt and pulleys. The motor 172 is preferably a permanent magnet type direct current electric motor. As shown in FIG. 3 the motorcompressor unit 150, the A.C. CONDENSOR 130, the receiver tank 134 and check valve 138 are connected in parallel with the DC. COMPRESSOR 152, the DC. CONDENSOR 160, the receiver tank 166, and the check valve 170. The check valves 138 and allow refrigerant to pass from the respective compressors into the refrigerant circuit and are provided to prevent one compressor from forcing compressed refrigerant, oils, and other materials which may be in the refrigerant circuit into the discharge of the other compressor. The outlets of the check valves are connected to a juncture point and from that point by a single conduit 140 to the inlet of the expansion valve or the like 142. Preferably, the compressors have the same horse power rating so that they will function substantially equally in the refrigeration system to evacuate the evaporator or cooling coil 146 and to compress the refrigerant.

Control of the auxiliary refrigeration power means is accomplished by a pressure activated control switch 174 communicably connected by a conduit 176 with the evaporator outlet conduit 148, the switch being electrically connected to control operation of the direct current electric motor 172. The pressure sensitive control switch is electrically connected with the motor 172 and communicably connected with the evaporator or cooling coil 146 to control operation of the motor 172. As the temperature in the refrigerated compartment varies, the pressure in the evaporator or cooling coil and its outlet conduit 148 will vary accordingly as is well known in the art, thus providing the activating initiative for the pressure sensitive control switch 174. The pressure sensitive control switch 174 has bellows or the like therein operably connected to open and close a pair of switches 178 and 180. The pressure sensitive control switch 174 is preferably adjustable to open and close the switches 178 and 180 at predetermined certain pressure values relative to the atmospheric pressure. The control circuit for the auxiliary refrigeration power means 14 further includes a storage battery 182, a master control switch 84 and a cooling fan having a direct current electric motor 185. A generator or the like 183 is provided for charging the battery 182, such is the generator of the vehicle on which the power means 14 is used. The cooling fan is preferably provided in suitable position to force air over the motor 172 and compressor 152 while they are in operation. Practice of this invention has shown the cooling fan to be helpful in reducing operating temperatures of the motor 172 and compressor 152 thereby providing for increased operating efficiency and prolonging their useful life. The storage battery 182 is connected to the compressor motor 172, the fan motor 186, the master control switch 184, and the switches of the pressure sensitive control switch 174. Closing the master control switch 184 completes the circuit connecting the storage battery 182 with the pressure sensitive control switch 174 and the motors 186 and 172. One control switch 180 in the pressure sensitive control switch 174 is electrically connected to control operation of the motor 172, and the other switch 178 is connected to control operation of the fan motor 186. An increase in temperature in the refrigerated compartment corresponds to an increase in pressure, relative to the atmosphere, in the evaporator or cooling coil 146 and also an increase in pressure in the conduit 184. When the pressure reaches a certain predetermined value, it causes the pressure sensitive control switch 174 to close the switches 178 and 180, thus connecting the storage battery 182 with the motors 172 and 186 so they will operate. As the compressor 152 operates, the temperature and pressure of the evaporator 146 are reduced. When a predetermined and certain pressure is reached in the refrigerated compartment, a predetermined and certain pressure is also reached in its outlet conduit 184 which causes the pressure sensitive control switch 174 to open the switches 178 and 180 thereby terminating operation of the motors 172 and 186, thereby stopping the compressor 152.

When the refrigeration system shown in FIG. 3 is operatcd from the alternating current power source 156, refrigerant circulates through the loop in the upper portion of the circuit as illustrated. Specifically, refrigerant passes through the compressor of the motorcompressor unit 150, to the AC. CONDENSOR 130, to the receiver tank or refrigerant storage container 134, through the check valve 138, through the expansion valve or th like 142, through the evaporator or cooling coil 146 and to the inlet of the compressor of the motor-compressor unit 150. The check valve 170 prevents compressed refrigerant from flowing into the outlet of the receiver tank 166 and thus into the compressor 152. When the auxiliary refrigeration power means 14 is in operation, the refrigerant flows through the outer loop ofthe circuit as illustrated in FIG. 3; specifically, from the compressor 152 to the DC. CON- DENSOR 160, to the receiver tank 166, through the check valve 170, through the expansion valve or the like 142, through the evaporator or cooling coil 146 and returns to the compressor 152. The check valve 138 prevents compressed refrigerant from passing into the outlet of the receiver tank 134 and thus into the compressor of the motor-compressor unit 150. In the circuit shown in FIG. 3 the refrigerant storage containers or receiving tanks 134 and 166 are provided for matching of the volumetric capacities of the compressors, condensors, and evaporator or cooling coil 146 to achieve an optimum result. It is to be noted that the specific ratings and capacities of the several elements of the entire refrigeration system can be picked to provide for a refrigerated compartment which is only slightly cooled, such as in the temperature range normally provided by household type refrigerators, water coolers, etc., or the subzero F. temperatures necessary for storage of frozen products such as ice cream and frozen foods.

In practice the refrigeration power means 14 has been constructed for use with a vapor compression refrigeration system for the freezing compartment of an ice cream vending truck of the type normally used for making street sales in residential areas. The freezing compartment when operated by the auxiliary refrigeration power means 14 maintains the temperature of same between -I2 F. and 3 F. which is a temperature suitable to maintain ice cream and similar confections in the solid frozen state. The auxiliary refrigeration power means has been used to maintain the temperature ofthe freezing compartment as described during periods of the summer when the outside air temperature is above l F. and the temperature inside the vending truck is 120 F. or higher. In such practice the compressors and the direct current electric motor are rated at approximately one-third /3) horse power. The pressure sensitive control switch 174 is preferably set to operate the compressor motor and compressor to maintain the above-described temperature conditions in the refrigerated compartment. In practice a halogenated hydrocarbon refrigerant, dichlorodifluoromethane, was used. In such practice the rcfrigerated compartment was a commercially available topopening chest type freezer of the general types described, supra. The motor-compressor unit is operated from normal line power, I I5 volts A.C. and the direct current motor 172 was operated from the i2 volt storage battery of the vehicle.

In the use and operation of the auxiliary refrigeration power means 14 of this embodiment, (3), of this invention, such-provides for powering the refrigeration apparatus from an alternating current power source or alternately from a storage battery. When an alternating current power source is available, the refrigeration system is operable from the power source via the motorcompressor unit 150. When an alternating current power source is not available or when it is desired to operate the refrigeration system from a direct current power source, the refrigeration system is operated by the auxiliary refrigeration power means 14 via the compressor 152 and connected motor 172. During times when an ice cream vending truck or the like is in a garage, or stored, or not in use, or being loaded, an alternating current power source is. generally available and at such time it can be connected with the motorcompressor unit 150 by an electrical cord and plug (not shown in the drawings) so that it will operate and at such time the master switch 184 should be put in the open position. During times when the truck is on the route or at a place where an alternating current power source is not available or at any other time when it is desired to operate same from the direct current power source, the master switch 184 is put in the closed position connecting the storage battery 182 in the electrical circuit. An additional feature of the auxiliary power means 14 is that in the event of a failure of the alternating current power source or a failure in the motorcompressor unit 150 or a related portion of the apparatus, then the refrigeration system can be operated by the auxiliary refrigeration power means 14 from the storage battery 182 by putting the master switch 184 in the on condition. Obviously, the storage battery of a vending truck or the like would not sustain a prolonged operation without recharging; however, it would provide a considerable time for repairs or to make other arrangements for frozen products of the refrigerated compartment.

Referring to FIG. 4 in detail, such shows an embodiment, (4), of the auxiliary refrigeration power means of this invention having the power means 16 integrally connected with a vapor compression refrigeration circuit. The auxiliary refrigeration power means is comprised of two portions, a first portion, generally indicated at 190, physically connected with the refrigeration circuit including a direct current electric motor, a compressor, and a thermostatic switch; and a second portion consisting of a power supply, indicated generally at 191. The refrigeration circuit and elements of the auxiliary refrigeration power means 16 in both portions and 191 are shown in schematic symbols or in representative diagram form to illustrate their connection and coaction. The vapor compression refrigeration circuit includes a compressor 192 connected by a conduit 194 to the condensor 196 which is connected by a conduit 198 to a receiver tank or refrigerant storage container 200, which is connected by a conduit 202 to an expansion valve or the like 204- which is connected by a conduit 206 to the evaporator or cooling coil 208 which is in turn connected by a conduit 210 to the inlet of the compressor 192. The condensor 196 is preferably a conventional free flow type structure; however, same may be a radiant shell type condensor. The compressor 192 is preferably a piston type compressor having a rotatable power input shaft. A direct current electric motor 212 is provided for rotation of the compressor shaft and is preferably connected thereto by a belt and pulleys. The electric motor 212 is preferably a permanent magnet type direct current electric motor. A cooling fan having a direct current electric motor 213 is provided to force air over the motor 212, compressor 192 and through the condensor 196. In the event a radiant shell type condensor is used, it is preferable that a fan be provided for cooling the motor 213 and compressor 192. The evaporator or cooling coil 208 is preferably constructed in the wall of the refrigerated compartment and may be varied in its specific structure depending upon the intended operation of the refrigerated compartment and the physical structure therefor. The expansion valve or the like 204 may be an expansion valve or a capillary tube, either of which function in a throttling process to expand the compressed refrigerant in a condition of substantially constant enthalpy. The receiver tank or refrigerant storage container 200 is provided as a refrigerant accumulator, such being an element commonly used in the art.

The first described portion 190 of the auxiliary refrigeration power means 16 includes the direct current electric motor 212, labeled D.C. MOTOR mechanically connected with the compressor 196 and further includes a thermostatic switch 214 having its temperature probe 216 adjacent to the coils of the evaporator 208. The thermostat or thermostatic switch 214 is preferably a conventional type of thermostatic switch com monly used in the refrigeration art which is adapted to open and close a switch at predetermined certain temperature values sensed by the probe.

The power supply portion 191 of the auxiliary power means 16 is shown in the upper portion of FIG. 4 above the dashed line. The function of the power supply portion 191 is to provide a source of direct current electrical power to operate the motor 212 and the thermostatic switch 214 either from an alternating current electrical power source or from a storage battery. The power supply portion 191 includes a power input, indicated at 220, connectable with an alternating current electrical power source, a rectifier portion, indicated generally at 222, to convert the alternating current electrical power into direct current electrical power, another input 221 from a storage battery 224, another input 223 from the thermostatic switch 214 and an output 225 to the motor 212 and the fan motor 213. The storage battery 224 is preferably a 12 volt storage battery of the type used on motor vehicles and the alternating current power source is preferably 115 volts, as indicated. A generator or the like 217 is provided for charging the battery 224, such is the generator of the vehicle on which the power means 16 is used. The

power supply portion 191 is constructed so that it will convert the alternating current into direct current to power the motors 212 and 213. It can be switched to operate the motors from the storage battery 224 while connected with the alternating current power source; and additionally it will automatically switch from the alternating current power source to the storage battery in the event ofa failure of the alternating current power source. The power supply portion 191 is provided with output connections 227 to operate a heater 226 on the lid portion of a freezing compartment with the output from the alternating current power source portion of the circuit. The heater 226 is provided 'on some models of commercially available freezers in the area of the lids or the doors thereof to prevent the doors from freezing shut. Connections for the heater 226 are included through the power supply portion 191 to make it more convenient for operating the freezing compartment from the power supply of the auxiliary refrigeration power means. The power supply portion 191 ofthe auxiliary refrigeration power means 16 is removably connectable with the mechanical portion 190 of the power means and such is indicated in FIG. 4 by the dashed line 219 extending transversely across the figure 1n the input portion of the power supply portion 191 a circuit breaker 228 is connected with the heater output 227. Another circuit breaker 230 is provided in the portion of the circuit connected with the rectifier portion 222. The rectifier portion 222 consists of a transformer 232 having a single input connected with the power supply input 220 and having two output stages connected with opposite sides of a diode bridge. The bridge has four diodes indicated at 233, 234, 235, 236, and capacitor 238 connected across the output thereof. As is well known in the art the output from the diode bridge shown is substantially direct current electrical power. A cooling fan having motor 240 is connected with the input side of the transformer 234 and used for cooling the transformer and the diodes of the rectifier. Preferably, the diodes 233, 234, 235, and 236 are mounted in a heat sink for dissipation of heat produced when in operation. A first relay 242 has the solenoid coil 243 thereof connected with the input side of the transformer 232 volts AC.) and has the contact terminals thereof connected with the output side of the bridge and the direct current portion of the circuit joining the motor 310. The first relay 242 is shown in the normally open or non-energized position. It has the normally open contact 244 connected with the positive output point of the diode bridge, the normally closed contact 246 connected with the positively charged portion of the circuit that is connectable with the storage battery- 224, and it has the switch arm 248 connected with a second relay 250. The second relay 250 has the coil 251 connected with the first relay switch arm 248 and the thermostatic switch 214. The second relay switch arm 252 is connected with the first relay switch arm 248. The relay 250 is normally open, as shown, and has its contact 254 connected with the electric motor 212. The relay 250 is used to connect the direct current electric motor 212 with the output of the rectifier portion upon command from the thermostat. Another loop of the power supply has the input 220 from the storage battery 224, a circuit breaker 256, and a master switch 258 in series with the first relay 242, the second relay 250 and the thermostatic switch 214. This loop of the circuit provides for operation ofthe electric motor 212 from the storage battery 224 with control by the thermostat 214. When the master switch 258 is closed and the rectifier portion 222 is not connected with an alternating current power source, the first relay 242 will be in the position shown in FIG. 4 and the second relay 250 in conjunction with the thermostat 214 will control current flow from the storage battery 224 to the electric motor 212. When the master switch 258 is open, this loop of the circuit will not affect operation of the rectifier portion 222 of the power supply, and it will not cause the electric motor 212 to operate. When the master switch 258 is open and the power supply input 220 is connected with the alternating current power source (l volts A.C.), the rectifier portion 222 supplies direct current for operation of the motor 212 and the thermostatic switch 214. The portion of the power sup ply portion 191 which is connected with the heater 226 is not affected by the rectifier portion 222. When the input 220 is connected with the alternating current power source, the cooling fan motor 240 will operate at all times and the first relay 242will be energized to the closed position wherein the switch arm 248 rests on the contact 244. The thermostatic switch 214 is connected with the negative output of the diode bridge, the negative output from the battery 224, and the coil 251 of the second relay 250. When the thermostatic switch 214 closes, it causes the second relay 250 to be energized thereby completing the loop of the circuit connecting the motor 212 with the output of the diode bridge via the first relay 242 and the second relay 250 to in turn cause operation of the motor 212. When the thermostatic switch 214 opens, the second relay 250 is opened thereby opening the just described loop of the circuit to in turn stop the motor 212. Opening and closing of the thermostatic switch 214 is controlled by temperature variations in the evaporator or cooling coil 208 as is common in the art.

It is to be noted that when the power supply portion 191 is connected with the alternating current power source and the master switch 258 is closed, the first relay 248 will be pulled to the closed position thereby obviating the'influence of the loop of the circuit connected with the storage battery 240. In the event of a failure of the alternating current power source, the first relay 242 will return to the open position thereby completing the loop of the circuit connected with the storage battery 224. When electrical power from the alternating current power source is restored, the first relay 248 will again be energized and thus return powering of the motor 212 to the rectifier portion 222 of the power supply. This feature ofthe auxiliary refrigeration power means 16 is an important feature of the invention in that it provides a backup for supplying electrical power to the motor 212. In the practice of this invention it has been used with ice cream vending trucks which are stored at night during periods of non-use in a garage and connected with the alternating current power source. In the event ofa failure ofthe alternating current power source, the power supply portion 191 will automatically switch as described to operate the electric motor 212 from the battery 224, particularly the vehicles storage battery, thus preventing loss of products stored in the refrigerated storage compartment.

In practice the auxiliary refrigeration power means 16 of this embodiment, (4), of this invention has been constructed and used in conjunction with ice cream vending trucks of the type used for street sales in residential areas. The refrigerated compartment is a commercially available top-opening chest type freezer; specifically, a model BF freezer produced by the Universal Noland Cabinet Company of Conway, Arkansas, has been used, and such is shown in cut away form in FIG. 6 and shown mounted in a vending truck in FIG. 7. In such practice the circuit breaker 228 connected with the heater 226 is rated at 2 amps. The circuit breaker 230 connected with the rectifier portion 222 is rated at 5 amps. The transformer 232 is preferably an iron core type transformer having l 15 volt primary windings and 12 volt secondary windings. The diodes 233, 234, 235, and 236 are preferably rated at lOO amps and volts, and the condensor 238 connected in the diode bridge is a computer type capacitor rated at 34,500 (microfarids) mf and 25 volts. The circuit breaker 256 is preferably rated at 30 amps. The motor 212 and compressor 192 are preferably rated at approximately one-third (V3) horse power. The motors 212 and 213 are permanent magnet type designed to operate on 12 volts.

FIG. 6 shows the described top-opening chest type freezer, indicated generally at 260, with portions thereof cut away and the auxiliary refrigeration power means 16 connected therewith. The freezing compartment is an insulated enclosure having upright walls 262 containing the evaporator coils 264 and having a top with a plurality of lids 266. The heater 226 is enclosed in the molding 268 for the lids 262. The auxiliary refrigeration power means mechanical portion is shown mounted on a tray 270 for facilitating ease in installation and removal from the freezer 260. The cooling fan having the motor 213 has a shroud around the blade portion thereof as shown positioned adjacent to the condensor 196. The cooling fan is preferably installed in a position to move air over the compressor 192, the motor 212 and through the free flow condensor 196; and it is connected in the electrical circuit as shown to operate at the same time as the motor 212. Depending upon the particular installation of the auxiliary power means 16 and the use therefor, the cooling fan may or may not be necessary; however, its use is preferred. The power supply portion 191 of the auxiliary refrigeration power means 16 is shown enclosed within a housing 272 and removably connectable with the mechanical portion 190 as described, supra. The master switch 256 is indicated on the face of the housing. A plurality of wires having removably connectable electrical connectors are shown for individually joining the several parts of the circuit, and they bear the same numerals as corresponding parts of the circuit shown in FIG. 4. It is to be noted that a single coupler incorporating the circuit connections 223, 225, and 227 can be used if desired. FIG. 7 shows the freezer 260 having the auxiliary refrigeration power means mounted in a van type truck indicated at 284. This style of van type truck is currently and properly used in the ice cream vending trade. The truck 284 is powered by an engine 285 and the engine 285 powers the generator or the like 217 which charges and maintains the vehicle storage battery 224. This general truck, generator or the like and storage battery powering system is preferred for powering the auxiliary refrigeration power means of this invention. The freezer 260 is preferably mounted on the drive side portion of the truck's interior with the power supply housing 272 mounted adjacent to the freezer structure. The removable electrical connections between the power supply portion 191 and the freezer 260 and the storage battery 224 provide a versatile installation in that separate portions thereof can be removed separately for servicing or replacement as units in a rapid manner. lee cream vending trucks having the auxiliary refrigeration power means and freezer apparatus as shown in FIG. 7 have been favorably used and proven to be commercially successful.

Referring to FIG. in detail, such shows an embodiment, (5 ofthe auxiliary refrigeration power means of this invention having the power means 18 integrally connected with a vapor compression refrigeration circuit. The auxiliary refrigeration power means 18 is comprised of two portions, a first portion, indicated generally at 290, mechanically connected with the refrigeration circuit including an electric motor, a compressor, a thermostatic switch; and a second portion consisting of a power supply assembly, indicated generally at 292. The refrigeration circuit and the elements of the auxiliary refrigeration power means 18 in both portions 290 and 292 are shown in schematic symbols or in representative diagram form to illustrate their connection and coaction. The vapor compression refrigeration circuit includes a compressor 294 connected by a conduit 296 to a condensor 298 which is connected by a conduit 300 to an expansion valve or the like 302 which is connected by a conduit 304 to the evaporator or cooling coil 306 which is in turn connected by a conduit 308 to the inlet of the compressor 294. The condensor 298 can be either a radiant shelltype condensor as shown or it can be a conventional free flow type condensor structure. The compressor 294 is preferably a piston type compressor having a rotatable power input shaft. A direct current electric motor 310 is provided for rotation of the compressor shaft, and it is preferably connected thereto by a belt and pulleys. The electric motor 310 is preferably a permanent magnet type direct current electric motor. A cooling fan having a direct current electric motor 312 is provided to force air over the motor 310 and compressor 294 for cooling. In the event the condensor 298 is a free flow type condensor, the fan is preferably positioned to force air through it. The evaporator or cooling coil 306 is preferably constructed in the wall or walls of the refrigerated compartment and may be varied in its specific structure depending upon the intended operation of the refrigerated compartment and the physical structure thereof. The expansion valve or the like 302 may be an expansion valve or a capillary tube, either of which function in a throttling process to expand the compressed refrigerant in a condition of substantially constant enthalpy. A receiver tank or refrigerant storage container may be provided in the refrigerant circuit depending upon the desire of the user and limitations of the refrigeration circuit.

The mechanically connected portion 290 of the auxiliary refrigeration power means 18 includes the direct current electric motor 310, labeled D.C. MOTOR which is mechanically connected to the compressor 294, and it further includes the thermostatic switch 314 having its temperature probe 316 adjacent to a coil of the coils of the evaporator 306. The thermostat or thermostatic switch 314 is preferably a conventional type element commonly used in the refrigeration art which is adapted to open and close a switch contained therein at predetermined certain temperature values sensed by the probe.

The power supply portion 292 of the auxiliary refrigeration power means is shown in the upper portion of 5 FIG. 5. The function of the power supply portion 292 is to provide a source of direct current electrical power to operate the motor 310 and the thermostat 314 from an alternating current power source or alternately operate them from a storage battery. The power supply 10 portion 292 includes a power input, indicated at 318,

connectable with an alternating current electrical power source, a rectifier portion, indicated at 320 to convert the alternating current electrical power into direct current electrical power, another input, indicated at 322, from a storage battery 324, another input 326 from the thermostatic switch 314, and an output 328 to the motor 310 and the cooling fan motor 312.

A generator or the like 325 is provided for charging the storage battery 324, such is the generator of the vehicle on which the power means 18 is used. The power supply portion 292 is constructed so that it will convert alternating current into direct current electrical power to power the motors 310 and 312. [t can be switched to operate the motors from the storage battery 324 while connected to the alternating current power source; and

additionally it will automatically switch from the alternating current power source to the storage battery in the event of a failure of the alternating current power source. The power supply portion 292 is provided with an output 330 to operate a heater 332 on the lid portion of the freezing compartment with the output being from the alternating current power source portion of the circuit. The heater 332 is provided on some models of commercially available freezers in the area of the lids or doors thereof to prevent the doors from freezing shut. Connections for the heater 332 are included in the power supply portion 292 to make it more convenient for connecting the freezing compartment with the power supply of the auxiliary refrigeration power means. Preferably, the power supply portion 292 of the I auxiliary refrigeration power means 18 is integrally mounted with the structure and electrical circuit of the freezing compartment structure so as to be permanently mounted therewith. Preferably, the wires and other electrical components of the auxiliary refrigeration power means are integral with the wiring harness and other structural elements of the freezing compartment, and electrical cable inputs are provided for connecting same with the alternating current power source and with the storage battery or direct current power source.

Referring to the upper portion of FIG. 5 which in detail shows the electrical circuit of the auxiliary refrigeration power means 18, such in the input portion thereof has a circuit breaker 334 connected with the heater output 330. Another circuit breaker 336 is provided in the portion of the circuit connected with the rectifier portion 320. The rectifier portion 320 consists of a transformer 338 having a single input connected with the power supply input 318 and having two output stages connected with opposite sides of a diode bridge. The bridge has four diodes indicated at 340, 342, 344, and 346 and a capacitor 348 connected across the output thereof. It is well known in the art that the output from the type of diode bridge shown is substantially direct current electrical power. A cooling fan having a motor 350 is connected with the input side of the transformer 338 and is used for cooling the transformer and the diodes of the rectifier. Preferably, the diodes 340, 342, 344, and 346 are mounted in a heat sink for dissipation of the heat produced when in operation. A first relay 352 has the solenoid coil 354 thereof connected with the input side of the transformer 338 (N volts AC.) and has the contact terminals thereof connected with the output side of the bridge and the direct current portion of the circuit joining the motor 310. The first relay 352 is shown in the normally open or nonenergized position. It has the normally open contact 356 connected with the positive output point of the diode bridge, the normally closed contact 358 connected with the positively charged portion of the circuit that is connectable with the storage battery 324, and it has the switch arm 360 connected with a second relay 362. The second relay has the solenoid coil 364 thereof connected with the first relay switch arm 360 and connected with the thermostat 314. The second relay switch arm 366 isconnected with the first relay switch arm 360. The second relay 362 is normally open, as shown, and has its contact 368 connected with the electric motor output 328 and in turn with. the electric motor 310. The second relay 362 is used to connect the direct current electric motor 310 with the output of the rectifier portion upon command from the thermostat 314. Another loop of the power supply circuit has the input 322 from the storage battery 324, a circuit breaker 370, and a master switch 372 connected in series with the first relay 352 and the second relay 362 and the thermostat 314. This loop of the circuit provides for operation of the electric motor 310 from the storage battery 324 with control thereof by the thermostat 314. When the master switch 372 is closed and the rectifier portion 320 is not connected with an alternating current power source, the first relay' 352 is positioned as shown in FIG. 5 and a second relay 362 in conjunction with the thermostat 314 will control the current flow from the storage battery 324 to the electric motor 310. When the master switch 372 is open, this loop of the circuit will not affect operation of the rectifier portion 320. When the master switch 372 is open and the power supply input 318 is connected with the alternating current power source, then the rectifier portion 320 supplies direct current for operation of the motor 310 and the thermostat 314. The portion of the power supply portion 292 which is connected with the heater 332 is not affected by the rectifier portion 320. When the input 3R8 is connected with the alternating current power source, the motor 350 for the rectifier cooling fan will operate at all times and the first relay 352 will be energized and its switch arm moved to the closed position wherein the switch arm 360 rests on the contact 356. The thermostat 314 is connected to the negative output of the diode bridge, the negative output of the storage battery 324, and the coil 364 of the second relay 362. When the thermostat 314 closes, it causes the second relay 362 to be energized thereby completing the loop ofthe circuit connecting the motor 310 with the output of the diode bridge via the first relay 352 and the second relay 362 to in turn start operation of the motor 310. When the thermostatic switch 314 opens, the second relay 362 is opened, thereby opening the just described loop of the circuit to in turn stop operation of the motor 310. Opening and closing of the thermostatic switch 314 is controlled by temperature variations in the evaporator or cooling coil 306 as is common in the art.

It is to be noted that when the power supply portion 292 is connected with the alternating current power source and the master switch 372 is closed, the first relay 352 will be moved to the closed position thereby obviating the influence of the loop of the circuit connected with the storage battery 324. In the event of a failure of the alternating current power source, the first relay 352 will return to the open position, thereby completing the loop of the circuit connected with the storage battery 324. When the electrical power from the alternating current power source is restored, the first relay 352 will again be energized and thus'return powering of the motor 310 to the rectifier portion 320 of the power supply. This feature of the auxiliary refrigeration power means 18 is an important feature of the invention in that it provides a back up for supplying elec trical power to the motor 310. In the practice of this invention it has been used with ice cream vending trucks which are stored at night during periods of non-use in a garage, and they are connected with the alternating current power source. In the event of a failure of the alternating current power source, the power supply portion 292 will automatically switch as described to operate the electric motor 310 from the battery 324, particularly the ice cream vending trucks storage battery, thus preventing loss of goods stored in the refrigerated compartment of the truck.

In practice the auxiliary refrigeration power means 18 of this embodiment, (5 of this invention is particularly well adapted for use in conjunction with ice cream vending trucks of the type used for street sales in -residential areas. This embodiment, (5), has been practiced with the refrigerated compartment being a commercially available top-opening chest type freezer, and with the elements of this invention in component form. Specifically, both of the hereinbefore described commercially available freezers have been operated by the auxiliary refrigeration power means 18. Obviously, the

specific ratings, sizes, and capacities of the several elements of the invention must be accordingly compatible with a particular freezer or freezing compartment used. Obviously, with the power supply portion 292 being integral with the freezer structure, the master switch 372 can be placed at a convenient position on the structure and the inputs thereto from the alternating current power source and the storage battery can likewise be made conveniently available so the freezer or freezing compartment can be installed and removed as a complete unit. Depending upon a particular installation of the auxiliary refrigeration power means 18 and the particular structure of the freezing compartment or freezer used therewith, the cooling fan for the motor 310 and compressor 294 may or may not be necessary; however, its use is preferred. When the condensor 298 is a radiant shell condensor, the cooling fan for the motor and compressor can be connected as shown in the electrical circuit to operate at the same time as the motor 310 to cool the motor and the compressor. When the condensor 298 is a free flow type condensor structure,

nient to incorporate such in the structure of the refrigerated compartment of a vehicle or in the refrigerated compartment structure itself.

In the manufacture of the auxiliary refrigeration power means of this invention, it is obvious that it can be constructed to be compatible with and operated with a refrigerated compartment to achieve the end product of providing a refrigeration system which can be operated from a direct current electrical power source. In practice the auxiliary refrigeration power means of this invention has been extensively practiced in conjunction with commercially available freezing compartments and used in ice cream vending trucks. lt is obvious that the auxiliary refrigeration power means of this invention can be constructed for refrigerators such as currently and popularly used in campers, motor homes, and the like. Additionally, it can be adapted for use with vehicles such as milk trucks, beer trucks, frozen food trucks, and other engine powered vehicles having refrigerated compartments and used for the transport of refrigerated or frozen food products or other goods which must be transported in a refrigerated condition. The specific motors, compressors, and other elements of the refrigerated system will obviously be variable dependent upon the particular application of the auxiliary refrigeration power means.

In the use and operation ofthe auxiliary refrigeration power means of this invention, it is seen that same provides an apparatus for operating a vapor compression refrigeration system from a direct current electric power source and alternately operating the refrigeration system from an alternating current electric power source. The auxiliary refrigeration power means is particularly well adapted for use with vehicles having refrigerated compartments because the apparatus provides a means of operating the refrigeration system for the refrigerated compartment from the vehicles storage battery and alternately operating the refrigeration system from a source of alternating current electrical power. In operation the auxiliary refrigeration power means of this invention can maintain the refrigerated compartment in a selected refrigerated condition regardless of which power source is being utilized. lt is obvious the auxiliary refrigeration power means fulfills a long-felt need in the art; namely, a refrigeration apparatus which can be operated from the electrical power of a vehicle and alternately operable from a readily available alternating current power source.

As will become apparent from the foregoing description of the applicants auxiliary power means apparatus, relatively simple means have been provided for the operation of a vapor compression refrigeration system wherein same is powered from a source of alternating current electrical power or alternately from a source of direct current electrical power. The auxiliary refrigeration power means apparatus is economical in that it has a minimum number of elements and utilizes standard commercially available parts and easily manufacturable elements. The apparatus is simple to use in that when connected with a refrigeration system it is substantially automatic and in all embodiments thereof can be used in the event of a power failure of the alternating source in order to maintain the refrigerated condition of the refrigerated compartment until the power is restored or to provide an extended time for other arrangements to be made for items stored in the refrigerated compartment.

While the invention has been described in conjunction with preferred specific embodiments thereof. it will be understood that this description is intended to illustrate and not to limit the scope of the invention. which is defined by the following claims.

I claim:

1. In an engine powered vehicle having a storage battery and a generator connected to said engine and battery, and a refrigerated compartment and a refrigeration system therefor including a cooling coil, a conipressor connected by a conduit to the outlet of said cooling coil, an alternating current motor operatively connected to said compressor, a condensor connected by conduit to the outlet of said compressor and to the inlet of said cooling coil, and an expansion valve or the like in the conduit to said cooling coil, the improvement therein and therewith, comprising:

a. a second compressor mounted on said vehicle, said second compressor connected to said condensor and said cooling coil in parallel with said first named compressor,

b. a direct electric motor mounted on said vehicle and operatively connected to said second compressor, said direct current motor being electrically connected to said storage battery and said generator in powered relation thereto, and

c. control means operatively connected to said system downstream of said second compressor and to said direct current motor to intermittently operate said direct current motor and second compressor relative the refrigeration demand of said system,

said second compressor is constructed and adapted to be operable during periods when said alternating current motor is disconnected from a source of alternating current electricity.

2(The refrigeration means of claim 1, wherein:

a. said refrigeration system has a first check valve means connected in said conduit from said outlet of said compressor to pass fluid from said compressor to said condensor, and

b. said refrigeration system has a second check valve means connected to the outlet of said second compressor to pass fluid from said second compressor to said condensor.

3. The refrigeration means of claim 2, wherein:

a. said control means has a pressure actuated switch means connected to said conduit between said cooling coil and said second compressor, said pressure actuated switch means is electrically connected to said direct current electric motor and to said battery,

b. said control means has a thermostat switch means communicably connected to said cooling coil, said thermostat switch being electrically connected to said alternating current electric motor to intermittently operate same, and

c. a cooling fan means is mounted with said vehicle for cooling said direct current electric motor and said second compressor, said cooling fan means having a direct current electric motor and being electrically connected to said pressure actuated switch means for simultaneous operation with said direct current electric motor.

4. The refrigeration means of claim 1 wherein:

a. said second compressor has a second condensor connected to the outlet thereof, said second condensor having the outlet thereof connected by conduit to said expansion valve or the like,

b. said refrigeration system has a first check valve communicably connected in said conduit between said first named condensor and said expansion valve or the like to pass fluid from said first named condensor to said expansion valve or the like, and

c. said refrigeration system has a second check valve communicably connected in said conduit between said second condensor and said expansion valve or the like to allow refrigerant to pass from said second condensor to said expansion valve or the like.

5. The refrigeration means of claim 4, wherein:

a. said control means has a pressure actuated switch means communicably connected to said conduit between said cooling coil and said second compres sor, said pressure actuated switch means is electrically connected to said direct current electric motor and to said storage battery,

b. said control means has a thermostat switch means communicably connected to said cooling coil, said thermostat switch being electrically connected to said alternating current electric motor to intermittently operate same, and

c. said refrigeration system has a cooling fan means for cooling said direct current electric motor and said first named compressor, said cooling fan means having a direct current electric motor and being connected to said pressure actuated switch means for operation simultaneously with said direct current electric motor.

6. In an engine powered vehicle having a storage battery and a generator connected to said engine and battery, and a refrigerated compartment and a refrigeration means therefor including a cooling coil, a compressor connected by a conduit to the outlet of said cooling coil, a condensor connected by conduit to the outlet of said compressor and to the inlet of said cooling coil, and an expansion valve or the like in the conduit to said cooling coil, the improvement therein and therewith comprising:

a. a direct current electric motor mounted on said vehicle and operatively connected to said compressor, said motor being electrically connected to said storage battery and said generator in powered relation thereto, and said motor being the only powering means for said refrigeration system,

b. rectifying means mounted on said vehicle and connected to said motor, such being constructed and adapted to convert alternating current to direct current, said rectifying means having means connectable to a source of alternating current electricity when said vehicle is normally not in use,

c. refrigeration demand control means operably connected to said system downstream of said compressor and to said motor to intermittently operate said motor relative to the refrigeration demand of said system, and

d. electrical control means operatively connected to said rectifying means and having means to connect said rectifying means to said motor when said rectifying means is electrically connected to said source of alternating current electricity, and having means to automatically change from powering said motor from said rectifier to powering said motor from said battery upon termination or interruption of said alternating current electricity, and having means to automatically change from powering said motor from said battery to powering said motor via said rectifying means when said rectifying means is connected to said source of alternating current electricity.

7. The refrigeration means of claim 6 wherein said refrigeration demand control means has a thermostat switch means thermally communicably connected to said cooling coil and electrically connected to said motor.

8. The refrigeration means of claim 7, wherein:

a. said electrical control means has a solenoid switch means with the solenoid coil thereof connected to the input of said rectifying means, and an input contact thereof connected to said battery, another input contact thereof connected to the output of said rectifying means and having an output electrically connected to said motor, and

b. said electrical control means has a second solenoid switch means having the solenoid coil thereof connected to said first solenoid switch means output and said thermostat switch means having an input contact thereof connected to said direct current electric motor, and having an output contact thereof connected to said first solenoid switch means output.

9. The refrigeration means of claim 6, wherein, said rectifying means is removably connectable with said motor, and a source of alternating current power. 

1. In an engine powered vehicle having a storage battery and a generator connected to said engine and battery, and a refrigerated compartment and a refrigeration system therefor including a cooling coil, a compressor connected by a conduit to the outlet of said cooling coil, an alternating current motor operatively connected to said compressor, a condensor connected by conduit to the outlet of said compressor and to the inlet of said cooling coil, and an expansion valve or the like in the conduit to said cooling coil, the improvement therein and therewith, comprising: a. a second compressor mounted on said vehicle, said second compressor connected to said condensor and said cooling coil in parallel wIth said first named compressor, b. a direct electric motor mounted on said vehicle and operatively connected to said second compressor, said direct current motor being electrically connected to said storage battery and said generator in powered relation thereto, and c. control means operatively connected to said system downstream of said second compressor and to said direct current motor to intermittently operate said direct current motor and second compressor relative the refrigeration demand of said system, said second compressor is constructed and adapted to be operable during periods when said alternating current motor is disconnected from a source of alternating current electicity.
 2. The refrigeration means of claim 1, wherein: a. said refrigeration system has a first check valve means connected in said conduit from said outlet of said compressor to pass fluid from said compressor to said condensor, and b. said refrigeration system has a second check valve means connected to the outlet of said second compressor to pass fluid from said second compressor to said condensor.
 3. The refrigeration means of claim 2, wherein: a. said control means has a pressure actuated switch means connected to said conduit between said cooling coil and said second compressor, said pressure actuated switch means is electrically connected to said direct current electric motor and to said battery, b. said control means has a thermostat switch means communicably connected to said cooling coil, said thermostat switch being electrically connected to said alternating current electric motor to intermittently operate same, and c. a cooling fan means is mounted with said vehicle for cooling said direct current electric motor and said second compressor, said cooling fan means having a direct current electric motor and being electrically connected to said pressure actuated switch means for simultaneous operation with said direct current electric motor.
 4. The refrigeration means of claim 1 wherein: a. said second compressor has a second condensor connected to the outlet thereof, said second condensor having the outlet thereof connected by conduit to said expansion valve or the like, b. said refrigeration system has a first check valve communicably connected in said conduit between said first named condensor and said expansion valve or the like to pass fluid from said first named condensor to said expansion valve or the like, and c. said refrigeration system has a second check valve communicably connected in said conduit between said second condensor and said expansion valve or the like to allow refrigerant to pass from said second condensor to said expansion valve or the like.
 5. The refrigeration means of claim 4, wherein: a. said control means has a pressure actuated switch means communicably connected to said conduit between said cooling coil and said second compressor, said pressure actuated switch means is electrically connected to said direct current electric motor and to said storage battery, b. said control means has a thermostat switch means communicably connected to said cooling coil, said thermostat switch being electrically connected to said alternating current electric motor to intermittently operate same, and c. said refrigeration system has a cooling fan means for cooling said direct current electric motor and said first named compressor, said cooling fan means having a direct current electric motor and being connected to said pressure actuated switch means for operation simultaneously with said direct current electric motor.
 6. In an engine powered vehicle having a storage battery and a generator connected to said engine and battery, and a refrigerated compartment and a refrigeration means therefor including a cooling coil, a compressor connected by a conduit to the outlet of said cooling coil, a condensor connected by conduit to the outlet of said compressor and to the inlet of said cooling coiL, and an expansion valve or the like in the conduit to said cooling coil, the improvement therein and therewith comprising: a. a direct current electric motor mounted on said vehicle and operatively connected to said compressor, said motor being electrically connected to said storage battery and said generator in powered relation thereto, and said motor being the only powering means for said refrigeration system, b. rectifying means mounted on said vehicle and connected to said motor, such being constructed and adapted to convert alternating current to direct current, said rectifying means having means connectable to a source of alternating current electricity when said vehicle is normally not in use, c. refrigeration demand control means operably connected to said system downstream of said compressor and to said motor to intermittently operate said motor relative to the refrigeration demand of said system, and d. electrical control means operatively connected to said rectifying means and having means to connect said rectifying means to said motor when said rectifying means is electrically connected to said source of alternating current electricity, and having means to automatically change from powering said motor from said rectifier to powering said motor from said battery upon termination or interruption of said alternating current electricity, and having means to automatically change from powering said motor from said battery to powering said motor via said rectifying means when said rectifying means is connected to said source of alternating current electricity.
 7. The refrigeration means of claim 6 wherein said refrigeration demand control means has a thermostat switch means thermally communicably connected to said cooling coil and electrically connected to said motor.
 8. The refrigeration means of claim 7, wherein: a. said electrical control means has a solenoid switch means with the solenoid coil thereof connected to the input of said rectifying means, and an input contact thereof connected to said battery, another input contact thereof connected to the output of said rectifying means and having an output electrically connected to said motor, and b. said electrical control means has a second solenoid switch means having the solenoid coil thereof connected to said first solenoid switch means output and said thermostat switch means having an input contact thereof connected to said direct current electric motor, and having an output contact thereof connected to said first solenoid switch means output.
 9. The refrigeration means of claim 6, wherein, said rectifying means is removably connectable with said motor, and a source of alternating current power. 